My kids like to play with Lego bricks on the floor, and sometimes a small piece will fall in to a heating register. Sometimes I can pull them out, but usually they fall too far, and there are sharp edges that like to draw blood.

Is there something I can do to block bricks from falling in, without interfering with air flow?

lego bricks peering in to the abyss


I like the idea of a smaller grate, but make life easy and get some regular fiberglass screen material at the hardware store and wrap the register cover with it and reinstall the cover. Cheap, easy and safe.

  • Is there fiberglass screen which doesn't significantly affect airflow? – wallyk Jul 16 '14 at 19:13

A mesh made of steel wire 2-3 millimeters in diameter with cells about 5 millimeters in size would solve the problem completely. If you can't find it readily available at a store you can spend some time soldering it on your own - will take time, but the result will be sufficient.

  • This will also keep rodents from entering and exiting the ductwork through the registers. – Matthew Sep 14 '12 at 15:04
  • 3
    Hardware Cloth is the technical name and 1/4" mesh (US measure) probably fits the ticket. Cut it to size to go under the register louver assembly (all the ones I've ever dealt with are lift out) and a 1 ft length will probably give you enough to protect 4 registers. The 1/4" mesh won't have too much restriction on the airflow, but should keep all but the littlest pieces from going down. You can get 1/8" mesh if you think a 1/4" opening is too large. – Fiasco Labs Sep 15 '12 at 1:52

Get some window screen mesh, you can buy it in rolls at the hardware store. Cut it so it forms a pocket below the register, and attach with velcro tape under the register to the side of the duct.

This should trap anything that falls through so you can lift the register and grab it easily. The window screen mesh shouldn't block the airflow in any significant way.

  • I worry that such a fine mesh would restrict the flow of air too much. I definitely feel the difference in breeze when a screen is over an open window. – Jay Bazuzi Jan 12 '12 at 2:12
  • This is something that I did in my house as there are some really large opening registers in the kids room. I put the mesh on the underside of the register and haven't noticed a change in air flow at all. – Scott Ramboz Jan 10 '19 at 17:28

An air deflector might make it harder for the Legos to find their way into the vent, just make sure you get one that wraps all the way around the vent to prevent Legos from sliding in along the floor.

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  • It might also make it more of a target, like carpet putting. :-) – wallyk Jul 16 '14 at 19:13

Growing up, my mom never let us play with Lego on the bare floor -- we had an old queen sized blanket that we spread out, then just grabbed the corners to lift it and store in a box for storage. It was easy to notice when the Lego were getting to the edge, and thus had to be pulled back in to the middle.

In this case, if you positioned the sheet so it went over the register, it'd block the register, but nothing would fall in while they were playing.


What about cutting the bottom out of a shoe box and then putting it around the register? (Kind of like those dog collars from the vet that prevent the dog from licking a wound/part of their body.) This would protect any pieces from rolling into the register (but also might encourage your kids to put more in). It definitely would not look the prettiest but maybe it would not matter for this room.

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